use hspec for testing

hamming.cabal

@@ -60,4 +60,5 @@ test-suite hamming-test
   build-depends:
       base >=4.7 && <5
     , hamming
+    , hspec >=2.11.9 && <2.12
   default-language: Haskell2010

package.yaml

@@ -56,3 +56,4 @@ tests:
     - -with-rtsopts=-N
     dependencies:
     - hamming
+    - hspec >= 2.11.9 && < 2.12

test/Spec.hs

@@ -1,2 +1,27 @@
+{-
+
+hamming
+Copyright (C) Jonathan Lamothe <jonathan@jlamothe.net>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as
+published by the Free Software Foundation, either version 3 of the
+License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public
+License along with this program.  If not, see
+<https://www.gnu.org/licenses/>.
+
+-}
+
+import Test.Hspec (hspec)
+
 main :: IO ()
-main = putStrLn "Test suite not yet implemented"
+main = hspec $ return ()
+
+--jl